本文選題：隨機(jī)激光器 + 隨機(jī)激光��； 參考：《電子科技大學(xué)》2016年碩士論文

【摘要】：在傳統(tǒng)的激光腔中,散射和無序結(jié)構(gòu)是無法避免的,雖然不利于激光的產(chǎn)生,但是卻可以實(shí)現(xiàn)隨機(jī)激光。傳統(tǒng)隨機(jī)激光的高激光閾值和無方向性限制了其應(yīng)用。與傳統(tǒng)隨機(jī)介質(zhì)相比,光纖的波導(dǎo)結(jié)構(gòu)可限制光徑向散射,實(shí)現(xiàn)高效的、低閾值的定向隨機(jī)激光輸出；此外,不同的光纖波導(dǎo)可提供便利、豐富的放大(如拉曼泵浦、稀土離子吸收能級(jí)泵浦)和反饋機(jī)制(如瑞利散射和光柵反射),是我們研究隨機(jī)激光的極佳平臺(tái),也為隨機(jī)激光的優(yōu)化和調(diào)控提供了靈活手段�；谝陨系脑�,本論文提出了一種新型的光纖波導(dǎo)結(jié)構(gòu)——引入隨機(jī)包層的圓柱波導(dǎo)結(jié)構(gòu),通過在毛細(xì)管內(nèi)表面涂覆無序?qū)?并將增益介質(zhì)(激光染料)溶液填充在纖芯,實(shí)現(xiàn)了低閾值、可調(diào)諧的隨機(jī)激光。增益和散射分離,構(gòu)成穩(wěn)定的激光器結(jié)構(gòu)。具體內(nèi)容如下所述：首先,通過軟件仿真設(shè)計(jì)的新型波導(dǎo)結(jié)構(gòu)完成理論仿真,分析模場(chǎng)和功率特性,完善隨機(jī)激光特性分析,優(yōu)化實(shí)驗(yàn)參數(shù)。證明了引入隨機(jī)包層的圓柱波導(dǎo)結(jié)構(gòu)支持多模傳輸。另外,隨機(jī)散射層的無序度越高,波導(dǎo)結(jié)構(gòu)束縛光子的能力越強(qiáng)。其次,詳細(xì)介紹了引入隨機(jī)包層的圓柱波導(dǎo)隨機(jī)激光器的制作。我們需要制作特殊的光纖。利用現(xiàn)有的空心毛細(xì)管和混有散射顆粒的粘合性溶液制成特定的隨機(jī)諧振腔,作為填充增益介質(zhì)的載體。選擇羅丹明B作為增益介質(zhì),設(shè)計(jì)增益控制裝置,完成隨機(jī)激光的實(shí)驗(yàn)系統(tǒng)。然后,引入隨機(jī)包層的圓柱波導(dǎo)隨機(jī)激光器激光特性研究。改變泵浦照射的位置或者改變?cè)鲆娼橘|(zhì)的濃度,可以實(shí)現(xiàn)不同波長(zhǎng)的激光輸出。移除新型的波導(dǎo)結(jié)構(gòu)中的散射顆粒,只有熒光,沒有任何激射現(xiàn)象。在這種光纖型光學(xué)結(jié)構(gòu)中,隨機(jī)包層提供多重散射將大部分光限制在增益區(qū),促進(jìn)隨機(jī)激射模的形成。系統(tǒng)提供一個(gè)開放的通道,能夠靈活選擇填充材料和散射機(jī)制。最后,光纖型隨機(jī)激光器的輸出功率對(duì)微流中散射體濃度敏感,在光傳感領(lǐng)域存在潛在的應(yīng)用。增益介質(zhì)中散射顆粒濃度影響激光的輸出強(qiáng)度,隨著增益介質(zhì)中散射顆粒濃度的增加輸出激光強(qiáng)度呈指數(shù)下降,提出了一種微小顆粒濃度的探測(cè)方法。
[Abstract]:Scattering and disordered structures are unavoidable in conventional laser cavities, which are not conducive to laser generation, but random lasers can be realized. The high laser threshold and directionality of traditional random lasers limit its application. Compared with the conventional random media, the waveguide structure of the fiber can limit the radial scattering of light and achieve high efficiency, low threshold directional random laser output. In addition, different fiber waveguides can provide convenience and rich amplification (such as Raman pumping, etc.) The rare-earth ion absorption level pumping and feedback mechanisms (such as Rayleigh scattering and grating reflection) are excellent platforms for the study of random lasers and provide a flexible means for the optimization and regulation of random lasers. Based on the above reasons, a novel fiber waveguide structure is proposed in this paper, which is the cylindrical waveguide structure with random cladding layer, which is coated with a disordered layer on the inner surface of the capillary tube and filled with the gain medium (laser dye) solution in the fiber core. A low threshold, tunable random laser is achieved. The gain and scattering are separated to form a stable laser structure. The main contents are as follows: firstly, the new waveguide structure designed by software simulation is simulated theoretically, the mode field and power characteristics are analyzed, the random laser characteristic analysis is improved, and the experimental parameters are optimized. It is proved that the cylindrical waveguide structure with random cladding supports multimode propagation. In addition, the higher the disorder of random scattering layer, the stronger the ability of binding photons in waveguide structure. Secondly, the fabrication of cylindrical waveguide random laser with random cladding is introduced in detail. We need to make special fibers. A special random resonator was prepared by using the existing hollow capillary tube and the adhesive solution mixed with scattering particles as the carrier of filling gain medium. Rhodamine B is selected as gain medium and gain control device is designed to complete the experimental system of random laser. Then, the laser characteristics of cylindrical waveguide random laser with random cladding are studied. Laser output at different wavelengths can be achieved by changing the position of the pump irradiation or the concentration of the gain medium. The scattering particles in the new waveguide structure are removed only by fluorescence without any excitatory phenomena. In this type of optical structure, the random cladding provides multiple scattering, limiting most of the light to the gain region, thus facilitating the formation of random stimulated modes. The system provides an open channel for flexible selection of filling materials and scattering mechanisms. Finally, the output power of the fiber random laser is sensitive to the concentration of scatterers in microflow, so it has potential applications in the field of optical sensing. The laser output intensity is affected by the concentration of scattering particles in the gain medium. With the increase of the concentration of the scattering particles in the gain medium, the output laser intensity decreases exponentially. A detection method for the concentration of small particles is proposed.
【學(xué)位授予單位】：電子科技大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2016
【分類號(hào)】：TN248

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本文編號(hào)：1850117